Sparking plug



Jan. 24, 1939. K. NlT rKA 2,144,891

SPARKING PLUG Filed July 25, 19:58

I n vernor': 4 7772 2 1? Patented Jan. 24, 1939 UNITED STATES SPARKING PLUG Karl Nittka, Wiesbaden, Germany Application July 25, 1938, Serial No. 221,211 In Germany July 6, 1937 I 3 Claims.

This invention relates to a sparking plug in which the insulator is made in known manner chiefly of pressed artificial resin, the central electrode being embedded in the artificial resin during the pressing and protected by annular mica plates against the action of the gases from combustion.

The object of the invention is, to improve these known sparking plugs and make them more suitable for practical use. This object is attained according to the invention by a novel shaping of the sparking plug whose main feature consists in that the insulator adapted to be inserted as a finished part has a tubular extension made in one piece with the insulator and also made of pressed artificial resin, the inner wall of which extension is covered by a hollow cylindrical packet of ring-shaped mica plates.

This construction presents the important advantage over the known sparking plugs of an absolutely resilient packing against the gases from combustion which remains constant in service and ailords ample electric insulation. The sparking plug according to the invention further differs advantageously from the sparking plugs of known constructions in that, owing to the shape described, it can he made at very little expense.

Another feature of the sparking plug according to the invention is that the insulator is held in the sparking plug body in known manner by a. ring pressed tightly into the screw threaded end of the sparking plug body, said ring bearing tightly against the mica plates. The advantage of this construction consists in the production of a permanent packing eflect with very simple constructional means.

According to the invention the method for the production of the sparking plug indicated, consists in that the mica plates in the form of ring discs and having a hole diameter equal to. the diameter of the central electrode which are pushed into an extension of the insulator and that the mica plates are bored to the diameter of the ignition space after the ring has been pressed in.

An embodiment of the invention is illustrated by Way of example in the accompanying drawing, in whieh:-

Fig. 1 shows the sparking plug in section,

Fig. 2 is a section through the insulator with central electrode.

The sparking plug according to the invention cznsists substantially of a metallic sparking plug body 6 in which an insulator a is introduced from below. The insulator has a shoulder 91 which bears against a flange g or the like on the upper end of the smooth continuous bore of the sparking plug body e. The insulator a is held in this position by a ring (1 which is pressed PATENT OFFICE tightly into the screw threaded end of the spark- 'ing plug body.

The insulator a is made of pressed artificial resin and inserted as a finished part. A tubular extension 2:; of the insulator a is made in one 5 piece with the insulator and also made of pressed artificial resin and it accommodates the central electrode b which is pressed into it and Whose upper end, provided with a screw thread for connecting to the ignition cable, projects from the insulator.

An earth electrode j which may be of any shape or arrangement, is accommodated in the The d.

' For packing the ignition chamber .1: against fie gases from combustion mica plates r are arranged in the tubular extension :171. These mica plates in the form of ring discs with .a hole in diameter equal to the diameter of the central electrode are pushed into the tubular extension 1'1. Hereafter the ring it is pressed in, whereupon the packet of mica plates is bored out to he diameter of the ignition chamber am. It is therefore possible to snake the ignition chamber of a predetermined size by boring to different widths and depths.

The particular advantage of the sparking plug according to the invention is the possibility of very simple manufacture and convenient assembly. The absolute and permanent gas-tight packing and the high resistance to puncture is also of importance.

I claim:-

l. A sparking plug, comprising in combination a metal body, an insulator of pressed artificial resin in said body, a central electrode embedded in said insulator during the pressing operation, a tubular extension on said insulator made in one piece with the same, and a hollow cylindrical packet of annular mica plates covering the inner wall of said extension.

2. A sparking plug, comprising in combination a metal body, an insulator of pressed artificial resin in said body, a central electrode embedded in said insulator during the pressing operation, a tubular extension on said insulator made in one piece with the same, a hollow cylindrical packet of annular mica plates covering the inner wall of said extension, and a ring in the end of said metal body bearing tightly against said mica plates and holding said insulator in said body.

3. A sparking plug as specified in claim 2, in which the mica plates consist of ring discs with a bore corresponding to the diameter of the central electrode, said bore after the insertion of said plates in said insulator extension being widened to the diameter of the bore in the ring and forming an ignition space.

KARL 

